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Title
Japanese:Thermodynamics and Kinetics of a Partial Peptide of K+ Channels: DFT Transition State Calculations Coupled with Temperature-Controlled Gas Phase Laser Spectroscopy 
English:Thermodynamics and Kinetics of a Partial Peptide of K+ Channels: DFT Transition State Calculations Coupled with Temperature-Controlled Gas Phase Laser Spectroscopy 
Author
Japanese: Yukina Suzuki, Keisuke Hirata, James M. Lisy, Shun-ichi Ishiuchi, Masaaki Fujii.  
English: Yukina Suzuki, Keisuke Hirata, James M. Lisy, Shun-ichi Ishiuchi, Masaaki Fujii.  
Language English 
Journal/Book name
Japanese:Bulletin of the Chemical Society of Japan 
English:Bulletin of the Chemical Society of Japan 
Volume, Number, Page Vol. 96    No. 3    pp. 310-317
Published date Feb. 2023 
Publisher
Japanese:The Chemical Society of Japan 
English:The Chemical Society of Japan 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL https://doi.org/10.1246/bcsj.20220345
 
DOI https://doi.org/10.1246/bcsj.20220345
Abstract K+ channels selectively conduct K+ at a high conduction rate, but not smaller Na+ and Li+. To provide an insight into the conduction mechanism previously, we experimentally observed the temperature dependence of the conformer distributions of a model peptide in K+ channels (Ac-Tyr-NHMe) complexed with alkali metal ions (Li+, Na+, K+, Rb+, and Cs+) by gas phase laser spectroscopy. The K+ and Rb+ complexes showed a more significant temperature dependence than the Li+ complexes, whose conformer distributions barely varied. This different behavior with temperature can be interpreted either thermodynamically (entropy vs. enthalpy) or kinetically (barrier height). Due to the lack of temperature dependence of the Li+ complex, we could not determine which factor, an enthalpy-driven structure or a high energy barrier, governs the Li+ complex?s behavior. To resolve this issue, we carried out DFT transition state calculations and time-dependent simulation of the metal complexes? conformer distributions based on the theoretical barrier heights. By comparing the experimental and computational data, the origin of the variation in the temperature dependence among different ion complexes was determined to be thermodynamic.

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